This invention relates to a method and an apparatus for forming, by plasma processing, fluorine added carbon film which can be used in interlayer insulating film of, e.g., a semiconductor device.
In order to realize high integration of the semiconductor device, methods such as miniaturization of pattern and/or multi-layer of circuit are being developed. Among these devices, there is the technology for allowing wiring to be of multi-layer. In order to achieve a multi-layer wiring structure, a conductive layer is connected between the n-th wiring layer and the (n+1)-th wiring layer, and a thin film called interlayer insulating film is formed within the area except for the conductive layer.
A typical interlayer insulating film SiO2 film. In order to allow the operation of the device to have higher speed in recent years, it is required to lower the specific dielectric constant of the interlayer insulating film. Studies with respect to material of the interlayer insulating film are being conducted. Namely, the specific dielectric constant of SiO2 is approximately 4 and studies have focused on the development of material having a specific dielectric constant smaller than that. Realization of SiOF having specific dielectric constant of 3.5 is being developed as one of them. The inventors of this application pay attention to fluorine added carbon film having a smaller specific dielectric constant.
Meanwhile, for the interlayer insulating film, high adhesiveness (adhesion), large mechanical strength and excellent thermal stability, etc. are required in addition to small specific dielectric constant. As fluorine added carbon, trade name Teflon (polytetrafuloroethylene) is well known. However, this material has extremely bad adhesive property and has small hardness. Accordingly, even if there is employed such an approach that fluorine added carbon film is used as an interlayer insulating film, there are many unknown portions in the film property (quality). In the present state, such material is difficult to be put into practical use.
This invention has been made under such circumstances and its object is to provide a method and an apparatus for manufacturing fluorine added carbon suitable for a semiconductor device.
This invention provides a plasma film forming method comprising the steps of: allowing film forming gas including compound gas of carbon and fluorine and hydro-carbon gas to be placed in plasma state; and forming an insulating film consisting of fluoride added carbon film on an object to be processed by the plasma.
This invention further provides a plasma film forming method comprising the steps of: introducing microwave of 10 kw or more per unit volume of 1 cubic meters within vacuum atmosphere into a plasma chamber of a plasma processing unit and of applying magnetic field thereto to allow plasma generation gas to be placed in plasma state by the electron cyclotron resonance; introducing the plasma into a film forming chamber of the plasma processing unit to allow film forming gas including compound gas of carbon and fluorine or compound gas of carbon, fluorine and hydrogen and hydro carbon gas to be placed in plasma state; and forming an insulating film consisting of fluorine added carbon film by the film forming gas placed in plasma state.
This invention further provides a plasma film forming method comprising the steps of: allowing film forming gas including compound gas of carbon and fluorine or compound gas of carbon, fluorine and hydrogen, and hydro carbon gas to be placed in plasma state within a vacuum vessel provided with a mounting table of an object to be processed; and applying, to the mounting table, bias power of 3.14 W/cm2 or more per unit area of the mounting surface of the mounting table to form an insulating film consisting of fluorine added carbon film on the object to be processed by the plasma while drawing ions in plasma into the object to be processed.
This invention further provides a plasma film forming method comprising the steps of: allowing processing gas including compound gas of carbon and fluorine or compound gas of carbon, fluorine and hydrogen, and oxygen plasma generation gas to be placed in plasma state; and forming an insulating film consisting of fluorine added carbon film onto an object to be processed by the plasma.
This invention further provides a plasma film forming method comprising the steps of: allowing film forming gas including compound gas of carbon and fluorine or compound gas of carbon, fluorine and hydrogen to be placed in plasma state to form an insulating film consisting of fluorine added carbon film on an object to be processed by the plasma; generating oxygen plasma after undergone switching from the film forming gas to oxygen plasma generation gas to etch a portion of the insulating film by this oxygen plasma; and generating plasma after undergone switching from oxygen plasma to the film forming gas to form an insulating film consisting of fluorine added carbon film on an object to be processed by this plasma.
This invention further provides a plasma film forming method comprising: applying a.c. power to processing gas to generate plasma; and forming a thin film on an object to be processed by the plasma while allowing the a.c. power by pulse having a frequency lower than frequency of the a.c. power to be turned on or off.
This invention further provides a plasma processing apparatus comprising: a plasma chamber for allowing plasma generation gas to be placed in plasma state; a first generator for generating microwave within the plasma chamber; a forming element for forming magnetic field within the plasma chamber; a first supply unit for supplying the plasma generation gas into the plasma chamber; a film forming chamber for forming an insulating film on an object to be processed; and a second supply unit for supplying film forming gas including compound gas of carbon and fluorine or compound gas of carbon, fluorine and hydrogen and hydro carbon gas into the film forming chamber, whereby the generation gas placed in plasma state by the electron cyclotron resonance by the microwave and the magnetic field is introduced into the film forming chamber so that the film forming gas is placed in plasma state, and an insulating film consisting of fluorine added carbon film is formed by the film forming gas placed in plasma state.